Pocket Butler

An AI-powered personal safety assistant that protects your belongings by detecting Bluetooth separation, triggering intelligent theft alerts, and helping users respond quickly to emergencies.

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Inspiration

Losing personal belongings or having them stolen is something many people experience, whether it's a backpack left behind, headphones forgotten in a café, or a phone being taken unexpectedly. Most existing tracking solutions only help after an item is already lost, requiring users to manually search for it.

We wanted to build a proactive personal security assistant that detects potential theft as it happens rather than after the fact. The goal was to create a mobile companion that quietly monitors trusted Bluetooth devices and immediately alerts the user when suspicious separation occurs.

What it does

Pocket Butler is an AI-powered personal safety assistant designed to help users protect their belongings.

The app allows users to pair trusted Bluetooth devices such as earbuds, smartwatches, or speakers and continuously monitors their connection in the background. If a protected device unexpectedly disconnects while protection mode is active, Pocket Butler triggers an anti-theft alarm after a configurable grace period. Key features include:

  • Bluetooth-based anti-theft monitoring
  • Background protection service
  • Intelligent disconnect detection
  • Configurable grace period before triggering
  • Loud native Android alarm
  • Secure PIN-based alarm dismissal
  • Real-time protection status
  • AI assistant integration for future personal safety and productivity features

How we built it

Pocket Butler was built as a Flutter application with native Android components for continuous Bluetooth monitoring and alarm execution.

The application combines:

  • Flutter for the user interface
  • Kotlin for Android background services
  • Bluetooth Classic APIs for connection monitoring
  • Foreground Services for reliable background execution
  • MediaPlayer and Android Audio APIs for alarm playback
  • Repository-based architecture for protection state management
  • Clean separation between Bluetooth monitoring, protection logic, and native alert execution

The Bluetooth monitoring system was redesigned during development to use device-level profile connection states instead of aggregate adapter states, making disconnect detection significantly more reliable across different Android devices.

Challenges we ran into

One of the biggest challenges was making Bluetooth monitoring reliable while the app runs in the background.

Android Bluetooth behavior varies between manufacturers, and profile connections are often established asynchronously. We redesigned our monitoring architecture to distinguish between temporary Bluetooth events and actual device disconnections, reducing false alarms.

Another significant challenge was alarm playback. Ensuring that the anti-theft alarm remains loud across different Android versions and OEM devices required careful investigation into Android's audio routing, foreground services, MediaPlayer configuration, and audio focus management.

Balancing background execution, battery efficiency, and responsiveness while following Android's security restrictions was another important engineering challenge.

Accomplishments that we're proud of

  • Built a reliable Bluetooth monitoring architecture
  • Developed a native Android background protection service
  • Reduced false disconnect detections through profile-aware monitoring
  • Created a secure PIN-protected alarm system
  • Designed a modular architecture separating monitoring, protection, and alert logic
  • Successfully integrated Flutter with native Android services

What we learned

Building Pocket Butler gave us a much deeper understanding of Android's Bluetooth stack, foreground services, audio routing, and background execution limitations.

We also learned the importance of designing systems around observations instead of assumptions, especially when working with asynchronous hardware events such as Bluetooth connectivity.

Finally, we gained valuable experience integrating Flutter with native Android components while maintaining a clean and testable architecture.

What's next for Pocket Butler

Our roadmap includes:

  • BLE device support
  • Wear OS integration
  • Smart location-aware protection modes
  • AI-powered theft risk detection
  • Cloud backup and device synchronization
  • Emergency contact notifications
  • Smart wearable integration
  • Cross-platform support for iOS

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